How to Clean a Dirty Engine Bay

How to Clean a Dirty Engine Bay

18th Sep 2015

What's your car's engine bay look like? Normally, only small amounts of dirt and debris will accumulate here, which should cause no reason for concern. But if you happen to leave the oil cap off, or if there the cam plug is leaking (a common occurrence among older model Honda Civics and Accords), oil may have spilled into the engine bay. Neglecting to clean it off can promote rust, eating through the surrounding components.

Cover it Up!

Don't make the mistake of popping the hood and spraying everything with water. This is often what drivers do at the first sign of spilled oil in their engine bay. In doing so, however, they expose sensitive components to moisture, potentially damaging them in the process.

Before you can clean the engine bay, you need to cover up the following components with trash bags and duct tape:

  • Alternator
  • Intercooler
  • Coil Packs
  • Electronic Control Unit
  • Air Intake Systems
  • Headlights
  • Electrical Plugs


Going back to the basics of high-school chemistry 101, water and oil do not mix. Therefore, attempting to clean oil by washing it off your engine bay generally doesn't work. You must first spray it with some type of degreaser, such as Simple Green. Just remember to use caution so it doesn't get on the paint. While degreaser is effective at eating through oil, it may also eat through your car's paint.


Using some small handheld detailing brushes, scrub the components that are covered in oil. This isn't going to completely clean them, but rather it will loosen the oil so it washes off more easily. You can purchase detailing


Last but not least, rinse your engine bay by spraying it with water. Assuming there's oil spilled here, you'll probably need to use a special car wash with a waste drain, as rinsing oil into the ground is illegal in most areas and could result in a fine. When you are finished, use a leaf blower to help dry up any remaining moisture, at which point you can remove the bags and duct tape covering the aforementioned components. Now you are good to go!

If this sounds like too much work, you can always take your car to a professional body shop to have them clean the engine bay. Many body shops carry steam cleaners that are used specifically for this reason. Rather than exposing your engine to high-pressure water, the body shop use a steam cleaner to remove any oil or debris. Prices for engine steam cleaning vary depending on the body shop and your location. However, most places charge somewhere between $75 and $200.

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